The consuming of a Big Mac from McDonald's, and shitting it out in a diarrhea
-ish manner later on that day, or the first thing next morning.
Ketchup: (yelling into the bathroom) Hey Beef whats taking so long?
Beef: Oh I just had a Big Mac man!
Beef: Its coming out of my ass right now, and I only had it a while ago! I'm having (yet another) Big Mac Shit Attack!
Ketchup: Ouch. I feel bad for the toilet after this one.
Beef: Yeah, me too.